Age bias exists even in outer space—in samples collected by Apollo astronauts

Because much of the evidence from Earth's early history has been destroyed by plate tectonics and weathering, astronomers often look to the moon and Mars for clues about our beginnings. But what if some of our information from those planets is biased?

When meteors crash into the moon, the impact creates so much heat that it melts the surface and spits up ejecta. Some of that melt product cools and eventually becomes shiny little orbs known as lunar glass spherules.

Ya-Huei - Huang - Graduate - Student - Earth

Ya-Huei Huang, a graduate student in earth, atmospheric and planetary sciences at Purdue University, looked to these spherules for clues about the rate of meteoroids crashing into the moon.

The samples she studied were collected by Apollo astronauts in the 1960s. Most of the spherules were relatively young, which might indicate that the rate of impacts on the moon has increased in the recent past – but Huang was skeptical of this interpretation, based on deliberations with co-author Nicolle Zellner, a researcher at Albion College.

Model - Formation - Distribution - Glass - Spherules

She created a model for the formation and distribution of lunar glass spherules and found that the impact rate on the moon has...